BTEX40 MODEL DEMONSTRATION PARAMETER SETS

Model: BTEX40, a single capillary 4-region 3-barrier blood-tissue exchange model

1. TABLE OF CONTENTS

See Parameters:

See Outputs:

See Diagram

See Model Demonstrations with parameter sets:

2. IMPORTANT !!! To run demonstration, enter "xhost +nsr.bioeng.washington.edu" in one of your windows to allow the demonstration program to open windows on your machine !!!

3. Parameters:

BTEX40 is parameterized as follows:

 

 

Parameter

Description

Typical Value

Units

Fp

Flow of plasma

1.0

ml/(g*min)

Vp

Volume of plasma

0.03

ml/g

V'ec

Virtual volume of endothelium

0.01-0.02

ml/g

V'isf

Virtual volume of ISF

0.15

ml/g

V'pc

Virtual volume of parenchymal cell

0.6-0.8

ml/g

PSg

Perm.*surface area (cap-ISF exchange)

1.0

ml/(g*min)

PSecl

Perm.*surface area (cap-endo exchange)

0.25

ml/(g*min)

PSeca

Perm.*surface area (endo-ISF exchange)

0.25

ml/(g*min)

PSpc

Perm.*surface area (ISF-cell exchange)

0.0 - 6.0

ml/(g*min)

Gp

Consumption in plasma

0.0

ml/(g*min)

Gec

Consumption in endothelium

0.0

ml/(g*min)

Gisf

Consumption in ISF

0.0

ml/(g*min)

Gpc

Consumption in parenchymal cell

0.0

ml/(g*min)

Dp

Diffusion constant in plasma

1.0E-05

cm^2/sec

Dec

Diffusion constant in endothelium

1.0E-05

cm^2/se

Disf

Diffusion constant in ISF

1.0E-05

cm^2/se

Dpc

Diffusion constant in parenchymal cell

1.0E-05

cm^2/se

Nseg

Number of segments along capillary

5-7

none

Clength

Characteristic capillary length

 

cm

C0

Initial concentration in all regions

0.0

 

Access to all variables is accessible by clicking the "INPUT" button on the main model page or by selecting "Inputsunder the "Parameters" menu.

 

4. Outputs:

Output variables are given by:

 

Output Variable

Description

Cin

The Input Concentration, plottable

Cout

The Outflow Concentration, plottable

Q

The amount of material in the capillary unit, plottable

Input area

The total amount of material in the input curve

Output area

The total amount of material in the outflow curve

Mean Transit time

The mean transit time of the BTEX40 unit, equals sum of connect volumes divided by the Flow and converted to seconds.

To plot results, select "Plot Area 1" from the Results menu. Place the cursor in an unused box nder Y-parameters and pressing the right mouse button will bring up a list of plottable parameters.

5. Diagram

 

 

6. Model Demonstrations with parameter sets:

The user should inspect the input parameters and the output curves. Output curves can be found under the Results button.

 

The following parameter sets are can be demonstrated by clicking on them:

6.1. Just the capillary is in use, no exchange into other regions: just_capillary.par

The output is just the input curve with a time delay of 1.8 seconds.

6.2. Capillary with diffusion: capillary_with_diffusion.par

The model is run twice. The first time is without diffusion in the plasma. The second time is with diffusion in the plasma. Multiple model runs are done by clicking on the "Model" Button, pulling down the menu and activating the "Run Config" button. Activate the "Inner Loop" button to see what parameters are being set.

6.3. Capillary plus isf +ec+pc, typical curve: all_exchange_regions.par

First just the capillary region, then the capillary + isf, then capillary + isf + ec, and finally Capillary + isf + ec + pc regions are all used, and their effect on the outflow is shown.

6.4. Comsumption in the cell versus consumption in the parenchymal cell: consumption_ec_vs._pc.par

The effects on outflow of (1) no consumption, (2) consumption in just the endothelial cell, and (3) consumption in just the parenchymal cell are plotted.

 

6.5. Optimization of data: btex40.opt.par

Open the results window to see data. Run model. Under Model (Upper Left), select "Optimize config ...". This will bring up the optimization window showing the details on the optimization. Go back to the main window and click on Optimize. Then run the model to see curve fit.

Copyright ©2000, National Simulation Resource, University of Washington, Seattle, WA, 98195-7962.
Last Modified on February 16, 2000
Written by Gary M. Raymond